Some of Best Buy's elderly customers who rely on the company's Jitterbug phones found themselves without cellphone service at the start of the year following changes to the mobile network the phones relied on.

The issues have led to numerous complaints on social media, with customers worried about being able to reach their loved ones and seniors potentially being left without a reliable form of communication during an emergency.

According to the Richfield-based electronics retailer, mobile network updates made on Jan. 2 have caused disruptions for some customers who still use the older model Jitterbug Flip phones.

"Nothing is more important to us than the safety of our customers, and as soon as we learned about the issue, we worked to notify customers that were potentially impacted," Best Buy said in a statement on Wednesday. "We're working to resolve the issue as quickly as possible."

On Best Buy's Lively website, which provides Jitterbug phones and medical alert devices mostly catered to seniors, a banner at the top of the homepage says the company is continuing to try to resolve the service disruptions. If a customer's phone is not working in the event of an emergency, customers are directed to "contact 911 directly via another phone device."

However, those responses haven't been enough for some users. On the official Lively Facebook page, one user commented, "I bought this phone for EMERGENCIES ... a lot of good it's doing me now."

Jitterbug Flip2 phones, Jitterbug smartphones and Lively-branded devices are not impacted by the service disruption.

Best Buy didn't provide any further details about the outage and how many customers are affected, but the loss of service appears to coincide with the prepared shutdown of Verizon's 3G mobile network. While the Lively website doesn't list Verizon as its carrier, back in 2009 when Lively was still called GreatCall, the company announced Jitterbug would run on Verizon's network.

Lively's website also says its phones are powered "by the nation's most reliable wireless network," a familiar phrase from Verizon's marketing.

In response to a comment on Twitter about Lively's issues and accusations that the company made the changes without warning, Verizon's support account replied: "Not without warning and various communications have been sent regarding any 3G phone running on our 3G CDMA network that is now retired."

Verizon has been publicly stating it would decommission its 3G network for years. The telecommunications provider originally announced it would shut down its 3G network in 2019, however, the company extended the shut off date to the end of last year "in order to care for our customers and give them every effort to minimize disruptions to their service as they moved to newer and more advanced technologies."

Until Jan. 1, impacted phones were still able to make 911 calls and calls to Verizon customer service, the company said.

Other mobile carriers such as AT&T also phased out their 3G networks last year as they made room for more advanced network services, including 5G.

Verizon said it notified customers of the changes through billing messages, digital and traditional outreach and also sent some customers updated devices proactively. In a post that was updated at the end of December, Verizon said fewer than 1% of it customers were still accessing the 3G network. It's not clear if these customers included Lively customers.

Best Buy has continued to expand its health division, including providing services and products for seniors. In 2018, Best Buy spent $800 million to purchase GreatCall, which would become Lively.

Lively customers with issues are encouraged to call 800-359-0476 or email customercare@lively.com.